Chitosan nonwoven fabric composited calcium alginate and adenosine diphosphate as a hemostatic bandage for acute bleeding wounds.

Acute bleeding following accidental injury is a leading cause of mortality. However, conventional hemostatic bandages impede wound healing by inducing excessive blood loss, dehydration, and adherence to granulation tissue. Strategies such as incorporating active hemostatic agents and implementing chemical modifications can augment the properties of these bandages. Nevertheless, the presence of remote thrombosis and initiators may pose risks to human health. Here, a hemostatic bandage was developed by physically combined chitosan nonwoven fabric, calcium alginate sponge, and adenosine diphosphate. The presented hemostatic bandage not only exhibits active and passive mechanisms for promoting clotting but also demonstrates excellent mechanical properties, breathability, ease of removal without causing damage to the wound bed or surrounding tissues, as well as maintaining an optimal moist environment conducive to wound healing. In vitro evaluation results indicated that the hemostatic bandage possesses favorable cytocompatibility with low levels of hemolysis. Furthermore, it effectively aggregates various blood cells while activating platelets synergistically to promote both extrinsic and intrinsic coagulation pathways. In an in vivo rat model study involving liver laceration and femoral artery injury scenarios, our developed hemostatic bandage demonstrated rapid clot formation capabilities along with reduced blood loss compared to commercially available fabrics.

Rational Design of High-Performance Keratin-Based Hemostatic Agents.

Keratins are considered ideal candidates as hemostatic agents, but the development lags far behind their potentials due to the poorly understood hemostatic mechanism and structure-function relations, owing to the composition complexity in protein extracts. Here, it is shown that by using a recombinant synthesis approach, individual types of keratins can be expressed and used for mechanism investigation and further high-performance keratin hemostatic agent design. In the comparative evaluation of full-length, rod-domain, and helical segment keratins, the α-helical contents in the sequences are identified to be directly proportional to keratins' hemostatic activities, and Tyr, Phe, and Gln residues at the N-termini of α-helices in keratins are crucial in fibrinopeptide release and fibrin polymerization. A feasible route to significantly enhance the hemostatic efficiency of helical keratins by mutating Cys to Ser in the sequences for enhanced water wettability through soluble expression is then further presented. These results provide a rational strategy to design high-efficiency keratin hemostatic agents with superior performance over clinically used gelatin sponge in multiple animal models.